New species found in Yosemite

Thursday

Oct 28, 2010 at 12:01 AM

YOSEMITE NATIONAL PARK - Scientists exploring caves in the tumbled piles of rocks around the sides of Yosemite Valley have discovered a new predatory arachnid species with scary, scorpion-style pinchers but no stinger and no eyes, according to a paper published Sept. 30 by the Museum of Texas Tech University.

Dana M. Nichols

YOSEMITE NATIONAL PARK - Scientists exploring caves in the tumbled piles of rocks around the sides of Yosemite Valley have discovered a new predatory arachnid species with scary, scorpion-style pinchers but no stinger and no eyes, according to a paper published Sept. 30 by the Museum of Texas Tech University.

Biologist Jean Krejca led the 2007 expedition, whose members were flipping rocks, doing a survey of the living organisms in Indian Cave, when they came upon a previously unknown species of pseudoscorpion.

"Usually, they have their claws open wide and they are in a defensive position," Krejca said.

Although Krejca is a veteran of cave expeditions and discoveries of species, she said it still was thrilling.

"Pseudoscorpions are one of the great things to find in caves because they are at the top of the food chain in a cave. It is like finding a lion out on the savannah in Africa."

This particular pseudoscorpion, named parobisium yosemite in the paper by Krejca and Texas Tech taxonomist James Cokendolpher, is about the size of a fingernail and has a reddish head and claws with a pale body. It joins 16 other species of pseudoscorpions found elsewhere in the United States, Korea, China and Japan.

The Yosemite pseudoscorpion is the only pseudoscorpion of its type found so far in talus caves and the second troglobite, a creature adapted to the cool, lightless conditions of caves.

Scientists say they still don't know much about parobisium yosemite.

Although the pseudoscorpion probably eats tiny insects and fellow arachnids, specimens taken to a laboratory mostly ignored potential prey they encountered. (Arachnids include spiders and scorpions and generally have eight legs, while insects have six.)

Another big question is how it got into the Yosemite caves. Those caves are only a few centuries old and are constantly changing as new rock falls occur along the steep walls of Yosemite Valley.

Krejca and Cokendolpher wrote in their paper that they didn't find the species in other nearby caves except for Elf Village Cave, less than half a mile away, also at the east end of Yosemite Valley.

Although the two talus caves are only a few centuries old, the scientists wrote that other, similar talus caves appear to have existed upslope nearby for about a million years and to have endured through several ice ages.

"Species take advantage of what niches there are available," Krejca said. "I think what is important to know about them is that it represents that there is still a lot to be learned that is here in our own backyard."